When comparing XMonad vs Gridsutra, the Slant community recommends XMonad for most people. In the question“What is the best window manager for Mac?”XMonad is ranked 15th while Gridsutra is ranked 28th. The most important reason people chose XMonad is:

XMonad is written, configured, and fully extensible in Haskell. This means that users aren't limited to a small set of pre-programmed layouts and actions: anything can be programmed into the configuration.
It's simple to modify basic settings, and the example config has lots of comments to get you started. Haskell keeps this code clean, concise, and readable, and its type system keeps you safe from any serious mistakes. This makes it fast and light, even on very small and slow systems.

Pros

Pro

Fully extensible with Haskell

XMonad is written, configured, and fully extensible in Haskell. This means that users aren't limited to a small set of pre-programmed layouts and actions: anything can be programmed into the configuration.

It's simple to modify basic settings, and the example config has lots of comments to get you started. Haskell keeps this code clean, concise, and readable, and its type system keeps you safe from any serious mistakes. This makes it fast and light, even on very small and slow systems.

Pro

Efficient to use

XMonad is a very minimal and efficient window manager, especially if the user is familiar with Haskell.

Pro

Edit configuration and reload on-the-fly

Configuration is compiled into the WM, and it can be changed/updated on-the-fly, without requiring a full reload.

Pro

Absolutely minimal

The entire window manager is extremely small, and includes nothing beyond basic window manipulation and tiling. Out of the box, there are no window decorations, status bar nor icon dock; just clean lines and efficiency.

Pro

Highly configurable

If you enjoy programming, you can even add features to XMonad to make it your perfect desktop environment, and the Contrib modules give you most of what you need to do exactly that.

Pro

Very stable

Use of Haskell, in conjunction with smart programming practices, guarantees a crash-free experience.

Pro

Handles multiple monitors well

XMonad can handle multi-monitor setups by default.

Pro

Great availability of libraries

The use of Haskell as an extension language means that popular pieces of functionality are easily shared and widely available as Haskell Libraries. Many default layouts, and tools for quickly and easily building your own, are available through XMonad-contrib, and highly re-usable configurations are commonly shared through blog articles and the Xmonad Wiki.

Pro

Xinerama support

XMonad has full support for Xinerama: windows can be tiled and managed across multiple physical screens.

Pro

Dynamic Tiling

XMonad uses dynamic tiling which means that it automatically handles arranging your windows into various layouts which the user can cycle through.

Pro

Good Adobe support

Gridsutra has Adobe support with the ability of stacking Adobe windows.

Pro

Simple UI

The interface if Gridsutra is well thought through and easy to use.

Pro

Window arrangement with a single click

Windows can be arranged or snapped in Gridsutra with a single click.

Pro

Intuitive UI and delightful user experience

Pro

A great tool for a reasonable price

Pro

Highly flexible

Gridsutra works with most MacOS applications.

Pro

Great drag and drop functionality

The drag and drop option in the layout gives freedom to the user for arrangement of any windows to any positions desired.

Pro

Useful ignore/unignore feature

The ignore / unignore feature in Gridsutra allows the user to block unwanted applications to be listed in the layout option.

Pro

Custom layout support

Cons

Con

Steep learning curve for uninitiated users

Like a lot of tiling window managers, the learning curve for XMonad is quite steep.

Con

Requires knowledge of Haskell for configuration

Understanding of Haskell is required in order to configure XMonad.

Con

Requires a lot of Haskell dependencies

XMonad depends on GHC (the Glasgow Haskell Compiler) which can take up about 700 MB or disk space.